Recurrence quantification analysis of uterine vectormyometriogram reveals differences between normal weight and overweight parturient women.

Objective: This study aims to use Recurrence Quantification Analysis (RQA) of uterine vectormyometriogram (VMG) created from the slow wave (SW) and high wave (HW) bands of electrohysterogram (EHG) signals and assess the directionality of the EHG activity (horizontal or X, vertical or Y) in normal-weight (NW) and overweight (OW) women during the first stage of labor.

Approach: The study involved 41 parturient women (NW=21 and OW=20) during the first stage of labor, all of whom were attended at the Gynecology and Obstetrics Hospital of the Maternal and Child Institute of the State of Mexico (IMIEM) in Toluca, Mexico. Twenty-minute EHG signals were analyzed in horizontal and vertical directions. Linear and nonlinear indices such as dominant frequency (Dom), Sample Entropy (SampEn), and RQA measures of VMG were computed for SW and HW bands.

Main results: Significant differences in SampEn and Dom were observed in the SW band between NW and OW in both X and Y directions, indicating more regular dynamics of electrical uterine activity and a higher dominant frequency in normal-weight parturient women compared to overweight women. Additionally, the RQA indices calculated from the VMG of SW were consistent and revealed that NW women exhibit more regular dynamics compared to OW women.

Significance: The study demonstrates that RQA of VMG signals and EHG directionality differentiate uterine activity between NW and OW women during the first stage of labor. These findings suggest that the uterine vector may become more periodic, predictable, and stable in normal-weight women compared to overweight women. This highlights the importance of tailored clinical strategies for managing labor in overweight women to improve maternal and infant outcomes. .